Exhaust ventilation systems can be used to remove effluents and air contaminants generated by cooking appliances. These systems are usually equipped with an exhaust hood positioned above the cooking appliance, the hood including a grease filter and an exhaust fan that removes effluents from the area where the cooking appliance is used. Certain exhaust ventilation systems can also function to prevent and/or suppress fires (such as grease fires) occurring on the cooking appliance or in the ventilation system itself. Some exhaust ventilation systems additionally include a cold water spray system to remove grease from the air and/or to clean one or more components of the system.
Efficiency of grease removal and/or cleaning and/or vapor condensation can depend on the temperature and/or dirt content of the water in the cold water spray system. Without reconditioning as to temperature and/or contamination content, the water's value for treating the effluent stream effectively decreases as it is used. For example, as the temperature of the cold water spray increases, the grease removal efficiency decreases. Accordingly, there is a need for maintaining and/or increasing cleaning efficiency of water by replacing or reconditioning, to ensure its effluent treatment competence.
A cold water spray system can also be advantageously used to provide a fire safety response; that is, to help suppress fires in the exhaust ventilation system. However, to provide this functionality, there is a need to accurately detect fires in and/or around the exhaust hood, and for activating the cold water spray system in response to detection of a fire.